Video processing method and video appliance implementing the method

Abstract

It is disclosed a video processing method for generating a reverse video stream from an original video stream. Coded frames of the original video stream are buffered and decoded, whereby a reverse video stream is generated wherein the decoded frames are organized according to an order which is opposite to the display order of the original video stream. According to the method, a frame to be displayed is selected (602) between frames of the original video stream, selection of the frame being made based on the frames display order of the reverse video stream. The method further provides for checking (702-703) in a list of decoded frames if all reference frames of the original video stream necessary to decode the selected frame have already been decoded and the relative decoded frames are actually buffered.

Description

DESCRIPTION[0001]1. Technical Field[0002]The present invention relates to the field of video processing methods and in particular to video processing methods for reverse play (rewind) of a video stream. The invention has preferred application in video appliances, like set-top-boxes, with limited memory available for video processing.[0003]2. Background Art[0004]Digital video streams consist of a plurality of video frames that shall be displayed in sequence; the higher quality of the video streams, the greater the size, in bytes, of the corresponding stream.[0005]In order to reduce required transmission bandwidth or required storage space, it is well known to compress video streams according to different compression standards.[0006]MPEG video employs three different compression algorithms for compressing frames: I-frames, which do not need other frames to be decoded (intracoded frames), P-frames, which need one previous P-frame to be decoded (intercoded frames), and B-frames, which n...

AI Technical Summary

Benefits of technology

The present invention provides a method for quickly rewinding a video stream to allow for smooth viewing. The method includes indexing the coded frames of the original video stream to define the display order and selectively decoding the frames. This allows for quick selection of video frames to be displayed. The technical effect of the invention is to improve video playback performance and user experience.

Problems solved by technology

In particular, such a problem is furthermore felt when the video appliance is required to support “trick modes”, i.e. playing (forward or reverse) of the video stream at different speeds.

Nevertheless, this solution has the drawback of a stepped video output which could be annoying for a user.

The solution proposed by U.S. 6,327,421 is not satisfactory because in order to obtain a smooth rewind of the video, it is necessary to generate an ancillary video stream with a lot of I-frames, which, as it is known, are not compressed too much.

This solution, therefore, cannot be used for a local rewind of a video stream, i.e. in a single video appliance that is not connected to a remote video server.

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